Stable Iron Isotope Studies in Rwandese Women Indicate That the Common Bean Has Limited Potential as a Vehicle for Iron Biofortification,

Abstract

Biofortification of plants is a new approach to combat iron deficiency. Common beans (Phaseolus vulgaris) can be bred with a higher iron concentration but are rich in iron absorption inhibitors, phytic acid (PA), and polyphenols (PP). To evaluate the potential of beans to combat iron deficiency, three iron absorption studies were carried out in 61 Rwandese women with low iron status. Studies 1 and 2 compared iron absorption from high and low PP beans, similar in PA and iron, fed as bean puree in a double meal design or with rice and potatoes as multiple meals. Study 3 compared iron absorption from high and normal iron beans with similar PP levels and a PA:iron molar ratio, fed with potatoes or rice in multiple meals. Iron absorption was measured as erythrocyte incorporation of stable iron isotopes. In study 1, iron absorption from the high PP bean (3.4%) was 27% lower (P < 0.01) than from low PP bean (4.7%), but when fed in multiple meals (study 2), there was no difference (7 and 7.4%, respectively; P > 0.05). In study 3, iron absorption from the high iron bean (3.8%) was 40% lower (P < 0.001) than from the normal iron bean (6.3%), resulting in equal amounts of iron absorbed. When beans were combined with other meal components in multiple meals, high PP concentration had no negative impact on iron absorption. However, the quantity of iron absorbed from composite meals with high iron beans was no higher than with normal iron beans, indicating that efficacious iron biofortification may be difficult to achieve in beans rich in PA and PP.

Biofortified Crops Can Alleviate Micronutrient Deficiencies: Review of Evidence from Randomized Feeding Trials

“…Total daily absorption of zinc (milligrams per day) from the biofortified maize was higher than for the control maize but did not differ from the fortified maize There was an increase in the amount of zinc absorbed in the diet of these children, the test group having the highest amount Quantities of zinc absorbed from iron biofortified pearl millet fed to children aged 2 years as the major food staple is more than adequate to meet the physiological requirements of these nutrients Rosado et al [32] Mexico 27 adult women with habitual diet high in phytates; Non pregnant or lactating…”

“…In the studies on iron biofortified crops the biochemical tests that were done to test improvement in the iron status were: Inflammation (measured by C-reactive protein and α-1-acid glycoprotein concentrations) [14,15], total body iron [13][14][15][16][17][18]21,22], haemoglobin concentration [16], serum ferritin concentration [13][14][15][16][17], acute phase proteins [18] and serum transferrin receptor concentration [19]. The baseline cut-offs for each of the parameter differed among the studies (Table 2).…”

“…Zinc biofortification studies used total daily zinc intake [31], dual isotope technique [30], stable isotope extrinsic labelling technique [30], and dual isotope tracer ratio technique [32].…”

“…The study subjects included young children (22-35 months); school going children [14][15][16], and adults, both male and females. The intervention periods, form in which the food was fed, and the feeding intervals for each of the studies differed.…”

“…The biofortified crops that were used in the studies were; Vitamin A (Orange) maize [25,26,29], vitamin A (yellow) cassava [24], Vitamin A (Orange) sweet potatoes [23,27,28], high iron beans [13,15,16,19,22], iron pearl millet [14,18,21], Zinc wheat [32], High iron rice [17], high zinc maize [31], High zinc millet [21] and high zinc beans [22].…”